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minio/pkg/donut/common.go

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3.3 KiB

/*
* Minimalist Object Storage, (C) 2015 Minio, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package donut
import (
"bufio"
"bytes"
"io"
"sort"
"strings"
)
// ProxyWriter implements io.Writer to trap written bytes
type ProxyWriter struct {
writer io.Writer
writtenBytes []byte
}
func (r *ProxyWriter) Write(p []byte) (n int, err error) {
n, err = r.writer.Write(p)
if err != nil {
return
}
r.writtenBytes = append(r.writtenBytes, p[0:n]...)
return
}
// NewProxyWriter - wrap around a given writer with ProxyWriter
func NewProxyWriter(w io.Writer) *ProxyWriter {
return &ProxyWriter{writer: w, writtenBytes: nil}
}
// Delimiter delims the string at delimiter
func Delimiter(object, delimiter string) string {
readBuffer := bytes.NewBufferString(object)
reader := bufio.NewReader(readBuffer)
stringReader := strings.NewReader(delimiter)
delimited, _ := stringReader.ReadByte()
delimitedStr, _ := reader.ReadString(delimited)
return delimitedStr
}
// RemoveDuplicates removes duplicate elements from a slice
func RemoveDuplicates(slice []string) []string {
newSlice := []string{}
seen := make(map[string]struct{})
for _, val := range slice {
if _, ok := seen[val]; !ok {
newSlice = append(newSlice, val)
seen[val] = struct{}{} // avoiding byte allocation
}
}
return newSlice
}
// TrimPrefix trims off a prefix string from all the elements in a given slice
func TrimPrefix(objects []string, prefix string) []string {
var results []string
for _, object := range objects {
results = append(results, strings.TrimPrefix(object, prefix))
}
return results
}
// HasNoDelimiter provides a new slice from an input slice which has elements without delimiter
func HasNoDelimiter(objects []string, delim string) []string {
var results []string
for _, object := range objects {
if !strings.Contains(object, delim) {
results = append(results, object)
}
}
return results
}
// HasDelimiter provides a new slice from an input slice which has elements with a delimiter
func HasDelimiter(objects []string, delim string) []string {
var results []string
for _, object := range objects {
if strings.Contains(object, delim) {
results = append(results, object)
}
}
return results
}
// SplitDelimiter provides a new slice from an input slice by splitting a delimiter
func SplitDelimiter(objects []string, delim string) []string {
var results []string
for _, object := range objects {
parts := strings.Split(object, delim)
results = append(results, parts[0]+delim)
}
return results
}
// SortU sort a slice in lexical order, removing duplicate elements
func SortU(objects []string) []string {
objectMap := make(map[string]string)
for _, v := range objects {
objectMap[v] = v
}
var results []string
for k := range objectMap {
results = append(results, k)
}
sort.Strings(results)
return results
}